As is well known, a soldering reflow vessel is often used in automatically mounting electric connectors to printed-circuit boards. Specifically, an electric connector is secured by a vacuum-suction nozzle, and the electric connector is adjusted in position and brought to a selected position in a printed-circuit board by the vacuum-suction nozzle. The electric connector is then released from the vacuum-suction nozzle by stopping application of negative pressure thereto. Then, gas is released inside the soldering reflow vessel, or infrared rays are radiated therein until the solder applied to selected conductors in the printed-circuit board has been melted, thereby soldering the solder tails of the electric connector to the selected conductors in the printed-circuit board.
As for the electric connector, if it has a flat top surface, such top surface is convenient for securement by a vacuum-suction nozzle as described above. Many electric connectors, however, have pin-like terminals projecting from their top surface, thus preventing the direct use of vacuum-suction nozzles.